1. Field of the Background
The present invention relates generally to a passive volatile material dispenser.
2. Description of the Background
Various volatile material dispensing devices are known that generally include a reservoir that holds a volatile material and may include a housing or support structure to retain the reservoir. These devices typically either allow passive diffusion of the volatile material to occur without the aid of a dispensing mechanism or enhance and/or facilitate the release of the volatile material using a dispensing mechanism. Often prior passive dispensers incorporate volatile materials into waxes and gel systems that dissipate during use. However, such media tend to be fragile and are susceptible to impact, extreme temperatures, and changes in humidity.
One answer to the fragility of such dispensers is to use a more robust medium, such as cellulose charged with one or more volatile actives. For example, one type includes a pre-scented or custom card insert made of paper (e.g., blotting paper), a non-woven porous material, or a synthetic carrier material such as extruded polyethylene or molded polystyrene that holds a volatile active. The card may be square or rectangular with parallel perforation lines extending between opposite sides of the card to allow the card to be easily rolled or formed to a size to be inserted into a roll of paper towels or toilet paper.
Another example includes an insect control article that has a substrate impregnated with a passively emanated active insect control ingredient selected from transfluthrin or other pyrethroids. The substrate may be paperboard, an open pore cellulosic material, coiled corrugated paper, and the like. The article may include hanger means and is preferably positioned within a room or similar space with air movement.
However, such prior art designs are poorly designed for maximizing emissions. For example, monolithic or minimally porous designs inhibit air flow through the dispenser. Similarly, such designs may only dispense volatile materials in a unidirectional fashion. Still further, such designs typically have static emission rates.
Attempts to improve upon these prior designs, for example, by increasing surface area to improve emission rates, have typically led to more complex dispensers. For example, certain dispenser devices, such as that shown in U.S. Application Publication No. 2012/0055075, are designed such that they can be folded and unfolded into three dimensional structures with one or more elements to repel flying insects, like mosquitoes. The devices are provided with a plurality of body sheets attached to each other at a plurality of locations. When fully open, the device presents a plurality of chambers with functional surfaces that may be treated with substances that attract, repel, or capture flying insects.
However, such complex dispensers require more materials and increased manufacturing steps for construction. It follows that complex dispensers are more expensive due to greater material costs due to multiple piece construction and greater labor costs due to their multiple step manufacture. Moreover, these complex dispensers create significant amounts of scrap material due to the multiple component pieces that have different shapes and sizes. There is a need, therefore, for passive dispensers that maximize the dispenser surface area exposed to air flow during use, without requiring unnecessary waste of materials or excessive manufacturing steps.